1. Field of the Invention
The Present invention relates to an analog electronic watch including a microcomputer. Particularly, the present invention relates to an analog electronic watch in which low consumption motor driving is controlled by a microcomputer.
2. Description of the Prior Art
Conventionally, in an analog electronic watch, in order to suppress consumed electric current of a motor, the width of a rectangular pulse is made variable or the duty of a chopping pulse is made variable as disclosed in Japanese Patent Unexamined Publication No. Sho. 54-101367, so that the motor is driven by minimal driving pulses. It is known that according to the chopping pulse, pulses are applied intermittently to a motor, so that the peak current of the motor is lowered as compared with the rectangular pulse.
However, in a conventional analog electronic watch, if the duty of the chopping pulse is raised by one rank, in the case of a base oscillation of 32 kHz, the pulse On-time is increased by multiplying 31 .mu.s by the number of chopping pulses, and further, the Off-time of the chopping pulse becomes narrow, so that the peak current is also raised and rather a large current loss is caused. Moreover, in order to make the duty more finely variable, an ineffective method, such as a method of forming a clock faster than a base oscillation by using a frequency multiplying circuit, has been performed.